Spatially resolved pharmacokinetic rate images of ICG using near-infrared optical methods

Alacam, Burak; Yazıcı, Birsen; Intes, Xavier; Nioka, Shoko; Chance, Britton

doi:10.1117/12.647205

Cited by 5 publications

(14 citation statements)

References 12 publications

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“…An important feature of the method introduced here is the direct reconstruction of the pharmacokinetic-rate images of optical fluorophores as opposed to voxel-by-voxel reconstruction algorithm that we reported in [21]. While the voxel-by-voxel algorithm can be modified to take into account spatial correlations in total concentration images, it does not take into account the temporal correlations present in dynamically changing fluorophore concentrations due to the decoupled nature of the two-step algorithm described above.…”

Section: B Related Work and The Advantages Of Our Approachmentioning

confidence: 99%

“…We analyze the computational complexity of the resulting algorithms (linear and nonlinear) and compare them with that of the voxel-by-voxel algorithm [21]. We evaluate the performance of our algorithms in numerical simulations using a tissue like numerical phantom.…”

mentioning

confidence: 99%

“…Recently, we reported ICG pharmacokinetic-rate images of three patients with breast tumors and demonstrated that the spatially resolved pharmacokinetic rates may provide superior information than a single set of rates obtained for the entire breast for cancer diagnosis [21]. We obtained ICG pharmacokinetic images in two steps.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Direct Reconstruction of Pharmacokinetic Rate Images of Indocyanine Green in Fluorescence Molecular Tomography

Alacam¹,

Yazıcı

Intes³

et al. 2006

Biomedical Optics

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Abstract-In this paper, we present a new method to form pharmacokinetic-rate images of optical fluorophores directly from near infra-red (NIR) boundary measurements. We first derive a mapping from spatially resolved pharmacokinetic rates to NIR boundary measurements by combining compartmental modeling with a diffusion based NIR photon propagation model. We express this mapping as a state-space equation. Next, we introduce a spatio-temporal prior model for the pharmacokinetic-rate images and combine it with the state-space equation. We address the image formation problem using the extended Kalman filtering framework. We analyze the computational complexity of the resulting algorithms and evaluate their performance in numerical simulations. An important feature of our approach is that the reconstruction of fluorescence concentrations and compartmental modeling are combined into a single step 1) to take advantage of the inherent temporal correlations in dynamic NIR measurements, and 2) to incorporate spatio-temporal a priori information on pharmacokinetic-rate images. Simulation results show that the resulting algorithms are more robust and lead to higher signal-to-noise ratio as compared to existing approaches where the reconstruction of concentrations and compartmental modeling are treated separately. Additionally, we reconstructed pharmacokinetic-rate images using in vivo data obtained from three patients with breast tumors. The reconstruction results show that the pharmacokinetic rates of indocyanine green are higher inside the tumor region as compared to the surrounding tissue.

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Section: B Related Work and The Advantages Of Our Approachmentioning

confidence: 99%

mentioning

confidence: 99%

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Direct Reconstruction of Pharmacokinetic Rate Images of Indocyanine Green in Fluorescence Molecular Tomography

Alacam¹,

Yazıcı

Intes³

et al. 2006

Biomedical Optics

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“…The source detector measurements in (9) are collected at discrete time instances, t = kT , k = 0, 1, ..., where T is the sampling period. Therefore, the continuous model described in (8) and (14) has to be discretized.…”

Section: Direct Reconstruction Of Pharmacokinetic Rate and Concenmentioning

confidence: 99%

“…In such cases, spatially resolved representation of pharmacokinetic rates may increase specificity and sensitivity compared to average bulk rates. Moreover, there are studies in literature showing that the spatially varying pharmacokinetics rates are quantitatively different inside and outside the tumor region [7]- [9].…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of Spatially Resolved Pharmacokinetic Rate Images of Fluorescence Agents in FDOT

Alacam

Yazıcı

Serdaroglu

et al. 2006

2006 International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-In this work, we propose a method to reconstruct spatially resolved pharmacokinetic rate images of fluorescence agents directly from the boundary photon flux measurements. We use a compartmental modeling scheme to model the pharmacokinetics of fluorescence agents. We coupled this model with the fluorescence diffuse optical tomography (FDOT) forward model to form a state space model which is then iteratively solved by extended Kalman filtering (EKF) algorithm. As an example, we used a two-compartment model for indocyanine green (ICG) pharmacokinetics. To validate the proposed method, we tested our approach using a simulation study. Reconstructed pharmacokinetic rate images with correct localization of heterogeneities and high reconstruction accuracy show that the proposed algorithm can be used for tumor detection, tumor diagnosis, drug delivery and feasibility studies.

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A simulation study of the variability of indocyanine green kinetics and using structurala prioriinformation in dynamic contrast enhanced diffuse optical tomography (DCE-DOT)

Ünlü

Birgül²,

Gülşen³

2008

Phys. Med. Biol.

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We investigated 1) the variability of the indocyanine green kinetics (ICG) between different cases in the existence of random noise changing the size of the imaging region, the location and the size of the inclusion, 2) the use of structural a priori information to reduce the variability. We performed two dimensional simulation studies for this purpose. In the simulations, we used a two-compartmental model to describe the ICG transport and obtained pharmacokinetic parameters. The transfer constant and the rate constant showed a wide variation i.e. 60% and 95% respectively when random Gaussian noise with a standard deviation of 1% in amplitude and 0.4 degrees in phase was added to data. Moreover, recovered peak ICG concentration and time to reach the peak concentration was different within different cases. When structural a priori information was used in the reconstructions, the variations in the transfer and the rate constant were reduced to 29%, 15%, respectively. As a result, although the recovered peak concentration was still case dependent, the variability of the shape of the kinetic curve was reduced.

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Spatially resolved pharmacokinetic rate images of ICG using near-infrared optical methods

Cited by 5 publications

References 12 publications

Direct Reconstruction of Pharmacokinetic Rate Images of Indocyanine Green in Fluorescence Molecular Tomography

Direct Reconstruction of Pharmacokinetic Rate Images of Indocyanine Green in Fluorescence Molecular Tomography

Reconstruction of Spatially Resolved Pharmacokinetic Rate Images of Fluorescence Agents in FDOT

A simulation study of the variability of indocyanine green kinetics and using structurala prioriinformation in dynamic contrast enhanced diffuse optical tomography (DCE-DOT)

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